The pertinent literature reports certain indeno[1,2-c]isoquinoline derivatives as products of degradation of alkaloid cryptopine [Perkin, W. H.: J. Chem. Sec. 109, 815 (1916); ibid. 115, 713 (1919); Dyke, S. F., Brown, D. W.: Tetrahedron 24, 1455 (1968)]. 11-H-indeno[1,2-c]isoquinoline and/or 5-hydroxy-11H-indeno[1,2-c]isoquinoline-N-oxide were prepared by reacting 11H-indeno[1,2-c]isocoumarine with ethanolic ammonia and/or hydroxylamine, respectively [Chatterjea, J. N., Mukherjee, H.: J. Indian Chem. Sec. 37, 379 (1960)].
5,11-dioxo-5,6-dihydro-11H-indeno[1,2-c]isoquinoline formed by reacting of 11-oxo-11H-indeno[1,2-c]isocoumarine with ethanolic ammonia under high pressure was described [Wawzonek, S., Stowell, J. K., Karll, R. E.: J. Org. Chem. 31, 1004 (1966)].
Indenoisoquinoline analogues of highly toxic nitidine and fagaronine have been also prepared [Cushman, H., Mohan, P., Smith, E. C. R.: J. Med. Chem. 27, 544 (1984); Cushman, M., Mohan, P.: J. Med. Chem. 28,1031 (1985)].
The named indenoisoquinoline compounds did not exhibit any useful biological activity with the exception of indenoisoquinoline analogues of fagaronine and nitidine which showed a weak antineoplastic action.
According to our knowledge, compounds of the present invention, 6-[X-(2-hydroxyethyl)aminoalkyl]-5,11-dioxo-5,6-dihydro-11H-indeno[1,2-c]i soquinolines of the general formula in which X stands for a number of carbon atoms from 0 to 5 in aminoalkyl group situated on nitrogen atom at position 6 of the indenoisoquinoline fundamental structure (eg bases of compounds of general formula I) and their salts with pharmaceutically and pharmaceutically acceptable acids, respectively, represent a new previously undescribed class of compounds which surprisingly showed a remarkable antineoplastic activities "in vitro" and "in vivo" which have not been described yet. The main advantage of new compounds is a great efficacy even after oral administration, low toxicity and in comparison with intercalating agents (antibiotics) synthetic attainability.